Back-pedaling brake.



No. 648,97l. v ,Patented may a, |900. c. H. m-zLvm..

A BACK PEDALING BRAKE.

' (Application medium' 19, 1899.) (No Model.) 2 Sheets-Sheet I.

. No. 648,97l. Patented may 8,1900. c. H. MELvIN.

BACK PEDALING BRAKE.

(Application Bled June 19, 1899.1

(No Model.) i 2 Sheets-Sheet 2` me imams verras co. vnnmuvnu.'wAsumm'mh'a c;

vvNITED STATES PATENT EEICE.

CHARLES II. MELVIN, OF ST. PAUL, MINNESOTA, ASSIGNOR TO FRANK M. SMITH,OF SAME PLACE.

BACK-PEDALING BRAKE.

SPECIFICATION forming part of Letters Patent No.648,971, dated May,`1900.

Application filed me 19,12'399.

To @ZZ whom, it may concern:

Beit known that I, CHARLES H. MELVIN, a citizen of the United States,residing at St. Iaul, in the county of Ramsey and State of Minnesota,have invented certain new vand useful Improvements in Bicycle-Brakes ;vand I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

My invention relates to what are known to the bicycle trade as combinedbrakes and coasters, which devices are found incorporated. as a part ofthe sprocket-,and-ehain driving mechanism of some lately-improvedbicycles. These sc -called combined brakes vand coasters have alreadybeen so constructed and applied to the driving-gear that the rider maycoast by holding 'the pedals against rotation, may set the brake by abackpedaling movement, and may drive the machine by the ordinaryforward-pedaling movement. These prior devices are subject toobjections, certain of which are obvious and certain others of whichwillappear later on in the following detail description.

My invention has for its object to remove certain objections hithertofound to prior devices of this general character and to provide a devicehaving greater efficiency and durability and to accomplish theseresultsv by a simple device which may be readily applied to bicycles nowin general use vas Well as to bicycles in the process of manufacture orbefore leaving the works.A 'These objects I accomplish by my invention,`which is illustrated in its preferred form in the accompanying drawings,wherein like characters indicate like parts throughout the severalviews.

Figure 1 is a right side elevation of a portion of a safety-bicycleequipped with my invention, some parts of the same being broken away.Fig. 2 is a detail part-ly in plan and partly in horizontal section,showing the righthand portion of the hub of the rear'or traction wheeland immediately-connected parts.

Figs. 3, 4, and 5 are transverse vertical sec tions taken on the line x3aof Fig. 2, but illustrating different positions of the parts. Fig. 0 isa transverse section taken on the line m6 :c6 of Fig. 5.4 Fig. 7 is atransverse sectionA Serin No. 721,014. (No man.)

taken on the line no? x7 of Fig. 5. Fig. 8 is a transverseverticalsection taken on the linev which it may be here stated isloosely mounted on the hub 2 of the said traction-wheel1. As is alsoordinary the rear or traction wheel is mounted on la spindle or axle 10,which is screw-threaded at its ends and securely held where set in theslots of the rear pronged forks 5 of the frame by means of nuts 11.Inthe illustration given set-screws 12, which work through brackets 13on the machineframe, give a graduated adjustment of the spindle or axle10to take up the slack of the chain. In its ends the hub 2 is providedwith internal annular ball seats or runways 14, with which cone-bearings15 on the screwt-hreaded ends of said spindle l0 cooperate to connethebearing-balls 16 in working position in the ordinary manner. shown,the right-hand end-of the hub 2 is reduced to form a shoulder 17. (Bestshown in Figs. 2 and 6.)

We are now to consider my features of improvement which go to make up mypresent One end-as l invention, herein illustrated in its preferredform.

Tightly screwed, preferably by right-hand threads d, onto the reducedright-hand end of the hub v2 and against the shoulder 17 is a ringorcollara', provided at its inner extremity with a peripheralclamping-flange 0,2. A clamping-flange inthe form of an annular nut orring b is secured by left-hand threads b on the still-further-redu`cedright-handend of the hub 2 and is tightly screwed against the adjacentedge or side of the collar or ring a. The purpose of using left-handthreads to secure this clamping nut or collar b onto the hub is, as willhereinafter appear, to

cause the same to tighten and not to loosen under the braking action. Anannular seat or channel having parallel sides is thus formed between theperiphery of the collar a' and the opposing faces of the cooperatingclamping flanges or parts a2 b. In this annular channel or seat anannular sprocket-wheel c is loosely mounted.

In its periphery the collar a is provided with pockets or recesses a3,and for coperation with said pockets the sprocket-wheel c is provided inits adjacent bearing-surface with pockets c', constructed as presentlymore specifically described. Metallic driving-balls d are placed in thepockets c.

At one extremity each pocket c is cut deep enough to permit thecoperating ball d to be loosely contained therein at times when theuncut peripheral portion of the collar ct is turned into line with saidpocket c', as shown in Fig. 4, for example. The other extremities ofsaid pockets c' (indicated in the drawings at 1C) and the opposingopposite extremities of the pockets a3, formed in the periphery of thecollar a and marked 3, are cut on a curve equal to the radius of thebearing-balls (I. In virtue of this construction it follows that whenthe balls d are thrown into operative driving positions, as indicated inFig. 3, they will be engaged and clamped between the opposin g andcorrespondingly-formed extremities lc and 8 of the cooperating-pocketsc' and d3, with the result that when said sprocket is driven in adirection to propel the wheel, and as indicated by the arrow marked onFig. 3, the Wheehhub, and hence, of course, the wheel, will bepositively driven in the same direction. Under such a driving actionthere will be practically no radial strains put upon either the sprocketc or the Collard', inasmuch as the said driving-balls are then soengaged that they do not produce a wed ging or cammin g action betweenthe surfaces which engage them. A very different action from thisisattained in the previous devices, wherein a friction-clutch is providedby wedging or causing the balls to engage with a wedging action betweendivergin g surfaces. With this wedging action, such as found in the saidprevious constructions, intensev strains are put upon the exteriormember of the clutch, and these exterior members are thus soon stretchedout of shape and rendered defective and in many cases broken.

In :my improved construction the inclined surfaces of the pockets esimply act to insure the proper delivery of the driving-balls d to thepockets a3 under the driving movement of the sprocket; but as soon asthey have delivered the said balls to said pockets a3 they have nofurther engagement with or action upon the said balls. On the otherhand, the bottoms of the pockets a3 are inclined or run gradually to theperiphery of the collar a simply to insure the proper return of thedriving-balls into thepocketsc, either under the coasting action, theback-pedaling or brakepedaling action, or whenever the sprocket c is runat a speed less than that at which the traction-whee1 is rotated. Inpractice I have found that it is better to make the pockets as concavein cross-section, and I nave also found it of the greatest importancethat the pockets c', particularly the inclined portions thereof, bestraight at cross-section. If the bottoms of the pockets c' arechanneled out to iit or approximately fit the curve of thedriving-balls, I have found that oil on becoming thick or sticky willhold the balls in said pockets and prevent the same from properlyoperating.

Ifrom what has been said'in the earlier part of this description it willof course be understood that the sprocket-chain 8 runs over thesprocket-wheel c. Workingbctween the outer face of the sprocket c andthe inner face of the clamping nut or flange bis an annular section f,which on account of the function which it performs I refer to as thebrakc plate. This brake-plate f has a stem portion f', which terminatesin jaws `or flanges f2, that are adapted to embrace and slide end- Wisefrom the adjacent rear bottom stay or tubular section et of the machineframe. These prongs or jaws f2 Hare in the direction of the stem f', sothat they engage the tubular framesection 4 only at their outer'ends,and thus leave them free to adjust themselves to said frame 2 as theyare slid endwise thereon by the adjustment of the rear wheel to take upthe slack of the chain. In the construction illustrated the prongs f 2are adapted IOO to be sprung over the frame-tube 4. Asis 4 obvious, withthis device the adjustment of the rear wheel may be made in theordinarymanner and the operator need pay no attention to the adjustment of thebrake-plate or other parts of my improved mechanism, as these`adjustments automatically take care of themselves.

In the inner face of the annular section l) ofthe so-called brake-plate,extending concentric to the axis of thespindle l0, is a shallow annulargroove or channelf, and in line with this channel f3 the adjacent faceof the sprocket c is provided with a series of cam grooves or pocketsc2. The cam grooves or pockets c2 are deep enough at one of theirextremities (marked 2C) to entirely contain the brake-balls g, which areseated therein, or at least to allow them to recede out of engagementwith the cam-channel f3 of the brakeplate f at times when they are notcalled into action to perform their assigned functions of applying orsetting the brake. At thei'r othei` extremities the cam grooves orpockets c2 are very shallow or entirely run out at the face of thesprocket.

It will of course be understood that if desired the prongs f2 may belined with leather or felt to prevent marring of the frame-tube 4. Itwill be further understood that my in- IIO vention is capable of manymodifications in its details of construction within the scope of theinvention.

Operation: The operation of the device above specifically described willbesnbstantially as follows: Under the ordinary pedaling motion, such asis given to the cranks in driving the machine ahead, the sprocketwheel cwill be driven, as indicated by arrows marked on Fig. 3, and thedriving-balls d will be dropped into operative positions, (shown in Fig.3,) and the action will be to positively connect the collar a/ on thehub 0f the traction-wheel with the said sprocketwheel and positivelypropel the said tractionwheel, as previously stated. Under this actionor movement of the sprocket-wheel the brake-balls g will be kept workedback into the deep extremities 2C of the camgrooves or "pockets c2, andhence, of course, there will be no tendency to set the brake. theoperator holds his feet and the pedals against rotation, and hence thesprocket c will be held against rotation, while the traction-wheel, itshub, and the collar a will continue to rotate in the direct-ionindicated by the arrow marked thereon in Fig. 4. Under this movement ofthe flange a the drivingballs d will be caused to recede into the deepextremities of the pocket c by the inclined bottoms of the pockets a3,so that no appreoiable resistance is offered to the rotation of the saidcollar d'. Furthermore, at this time, as there is no movement of thesprocket with respect to the brake-plate f, the brake-balls g willremain in the deep extremities 2 of the cam-pockets c2, as also shown inFig. 4, and hence the brake will not be applied in coasting or as longas the sprocket c is held stationary or against backward rotation.

A In fact, in coasting the pedals may be rotated in the direction todrive the wheel, but at a lower rate of speed than that at which thetraction-wheel is rotated, and the actions of the driving clutch deviceand of the brakesetting device will be substantially the same as if thepedals were held stationary or against rotation.

The brake is very readily set by back-pedalin g, so as to move thesprocket c in the direction indicated by the outside arrow, (markedonFig. 5,) which movement causes the brakeballs g to crowd against andinto the channel f3 of the brake-plate f and crowd their way toward theshallow extremities of the cam pockets or grooves c2, as shown in Figs.5 and 7. The harder the cranks are back-pedaled the harder the brakewill be set. In this brake-setting action the brake-balls in crowdingwith a wedge action between the channel or groove f3 and the inclinedbottoms of the cam pockets or grooves c2 force the innermost side of thesprocket tightly into frictional engagement with the clamping-flange a2of the collar c and force the flat outer surface of the brake-plate finto frictional engagement In coasting with the inner surface of theclamping ring or flange b. In this manner the surface, which isfrictionally engaged to set the brake or in the brake-setting action, isdistributed over considerable area, so that no great amount of wear willcome at any particular point. The efficiency of the brake is also thusgreatly increased.

The efficiency of the device above described is thought to be obvious.The simplicity of the device is also an obvious feature.

My improved brake and coaster adds but very slightly to the ordinarycost of a bicycle and occupies but very little room, and, furthermore,it may be applied to almost any form of cycle-wheel hub and in no oaserequires any objectionable construction as incident to its applicationto a bicycle.

It will be furtherunderstood that my improved coaster and brake is notlimited to use in connection with sprocket-chain-driven bicycles.

What I claim, anddesire to secure by Letters Patent of the UnitedStates, is as follows:

l. In a cycle, the combination with a pair of laterally-spacedfriction-anges on the hub of the traction-wheel, of a driving memberloosely mounted on the said hub between said friction flanges, ananchored brake-plate working between said driving member and one of thesaid friction-anges,a one-way driving-clutch connecting said drivingmember and said wheel-hub, and a reversely-acting friction brake devicecomprising profile camgrooves in the face of the driving member adjacentto said brake-plate, and balls working in said profile cam-grooves andadapted by backward rotation of the said driver to be clamped betweenthe same and said brakeplate, substantially as described.

2. In a cycle, the combination with the hub 2 provided with thelaterally-spaced frictionflanges b and a2, of the sprocket c looselymounted on said hub between said lianges, said sprocket having theinternal seats or notches c and the profile cam-grooves c2, theplurality of driving-balls d working in said seat c and coperatingrecesses a3 in the said hub,the brake-platef working on said hub betweenthe outer face of said sprocket c and the said friction-flange b, andthe brake-setting balls g within the profile cam-grooves c2 IDO IIO

of said sprocket, which balls g2 ai'epressed being in the form of a ringmounted on said dri-ven member and provided with a series of internalball-seats and provided also with a series of profile or sidecam-grooves on one face thereof, friction-anges on said driven memberembracing said driver, an` anchored or relatively-iixed brake plate or`member posi- 'tioned between one of said friction-flanges and the proleoztnrgrooves of said driver, a series of driving-bn11s in the internalball-seats of said driver operative on said driven member In testimonywhereof I affix my signature in presence of two Witnesses.

under driving movements of said driver, and CHARLES II. MELVIN. 5 n,series of driving-balls in the proie eamgrooves of said driver operativeon said brake \Vitnesses:

plate or member under backward rotations of M. M. MCGRORY,

Said drivel', substantially as described. F. D. MERCHANT.

